PCI/sysfs: Fix double free in error path

commit aa382ffa705bea9931ec92b6f3c70e1fdb372195 upstream.

When pci_create_attr() fails, pci_remove_resource_files() is called which
will iterate over the res_attr[_wc] arrays and frees every non NULL entry.
To avoid a double free here set the array entry only after it's clear we
successfully initialized it.

Fixes: b562ec8f74e4 ("PCI: Don't leak memory if sysfs_create_bin_file() fails")
Link: https://lore.kernel.org/r/20221007070735.GX986@pengutronix.de/
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 7fb5cd1..f2909ae 100644 (file)
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1179,11 +1179,9 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine)
 
        sysfs_bin_attr_init(res_attr);
        if (write_combine) {
-               pdev->res_attr_wc[num] = res_attr;
                sprintf(res_attr_name, "resource%d_wc", num);
                res_attr->mmap = pci_mmap_resource_wc;
        } else {
-               pdev->res_attr[num] = res_attr;
                sprintf(res_attr_name, "resource%d", num);
                if (pci_resource_flags(pdev, num) & IORESOURCE_IO) {
                        res_attr->read = pci_read_resource_io;
@@ -1201,10 +1199,17 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine)
        res_attr->size = pci_resource_len(pdev, num);
        res_attr->private = (void *)(unsigned long)num;
        retval = sysfs_create_bin_file(&pdev->dev.kobj, res_attr);
-       if (retval)
+       if (retval) {
                kfree(res_attr);
+               return retval;
+       }
+
+       if (write_combine)
+               pdev->res_attr_wc[num] = res_attr;
+       else
+               pdev->res_attr[num] = res_attr;
 
-       return retval;
+       return 0;
 }
 
 /**